Radio Vortex–Multiple-Input Multiple-Output Communication Systems With High Capacity

As a potential technique to improve channel capacity, orbital angular momentum has been developed in the radio field. In this paper, a novel radio vortex–multiple-input multiple-output (RV-MIMO) system is proposed to provide high capacity in free space. In particular, the vortex channel of the proposed system is modeled. Based on this model, the optimal vortex phase is derived, which results in the optimal capacity of the proposed RV-MIMO system. Simulation results show that the proposed RV-MIMO system could achieve higher capacity than the MIMO system in free space.